Two-Piece Focusing Ring for Etching Rate Stability

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Solution Overview

Problem

The stability of the etching rate in semiconductor etching chambers with a two-piece focusing ring structure is compromised due to plasma-induced deposition of ceramic material on the chamber walls, leading to significant deviations and reduced service life, which affects the uniformity and cost-effectiveness of the etching process.

Innovation Solution

A method involving a first one-piece focusing ring for fatigue damage testing to determine a damage range, followed by a two-piece focusing ring structure with the second outer protection ring's surface positioned outside the damage range to prevent material deposition, ensuring the stability of the etching rate and extending the service life of the ceramic material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If a two-piece focusing ring structure with ceramic outer protection ring is used, then the service life of the focusing ring is extended and cost is reduced, but the etching rate stability deteriorates due to plasma-induced deposition on chamber walls

Engineering Contradiction:

Improveservice life of focusing ringVSAvoidetching rate stability

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The focusing ring is divided into two separate pieces: an inner concentration ring and an outer protection ring. This segmentation allows each component to have optimized material selection and positioning, where the outer protection ring can be strategically placed outside the damage range to prevent plasma-induced deposition while the inner concentration ring maintains etching concentration functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different material properties are assigned to different parts of the focusing ring structure. The outer protection ring uses ceramic material with long service life positioned in the non-damage zone, while the inner concentration ring uses material optimized for etching concentration. This local differentiation resolves the contradiction between durability and etching rate stability.

Inventive Principle:

Principle #3Local quality

2Reliability

If the outer edge of the first concentration ring is positioned to cover the damage range, then the ceramic material is protected from plasma bombardment, but the structural complexity increases

Engineering Contradiction:

Improveprotection from material depositionVSAvoidfocusing ring structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The outer protection ring is pre-positioned to extend beyond the damage range before the etching process begins. This preliminary positioning ensures that the ceramic material is already in place to protect against plasma bombardment, eliminating the need for complex real-time adjustment mechanisms or monitoring systems.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If a one-piece focusing ring structure is used, then the structure is simpler and easier to manufacture, but the service life is reduced due to uniform material exposure to plasma damage

Engineering Contradiction:

Improvefocusing ring manufacturingVSAvoidservice life of focusing ring

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The focusing ring is segmented into two independently manufacturable components that can be produced using optimized processes for each material type, then assembled together. This segmentation allows each component to be manufactured with appropriate techniques for its specific material properties, simplifying overall manufacturing while extending service life through differential wear resistance.

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach stabilizes the etching rate by preventing ceramic material deposition on the chamber walls, maintaining the required etching rate deviation and extending the service life of the focusing ring components, thus reducing process costs and improving the structural integrity of the etching chamber.

Implementation Method 1

the plasma will bombard the ceramic material of the second outer protection ring 201b under the high bias voltage

Methodology Applied

Scientific EffectPlasma bombardment: Plasma

Implementation Method 2

the metal in the ceramic material will be deposited on the inner wall of the chamber

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Implementation Method 3

the second outer protection ring's surface positioned outside the damage range to prevent material deposition

Methodology Applied

Scientific EffectPhysical barrier protection: Physical Containment

Data Source

PatentUS20230162995A1Method for Improving Stability of Etching Rate of Etching Chamber

Publication Date: 2023.05.25 SHANGHAI HUALI MICROELECTRONICS CORP

AI summary

The present application discloses a method for improving stability of etching rate of an etching chamber, which includes the following steps: step 1: providing a first focusing ring with a one-piece structure; step 2: performing a fatigue damage test to the first focusing ring; step 3: disposing a second focusing ring with a two-piece structure according to the damage range, the second focusing ring consisting of a first concentration ring and a second outer protection ring, the material of the first concentration ring being the same as the material of the first focusing ring, the diameter of the outer edge of the first concentration ring extending to a position where the damage range is at least completely covered; step 4: performing an etching process by adopting the etching chamber with the second focusing ring.